Distoseptispora xinpingensis H.W. Shen & Z.L. Luo, 2024

Shen, Hong-Wei, Bao, Dan-Feng, Boonmee, Saranyaphat, Lu, Yong-Zhong, Su, Xi-Jun, Li, Yun-Xia & Luo, Zong-Long, 2024, Diversity of Distoseptispora (Distoseptisporaceae) taxa on submerged decaying wood from the Red River in Yunnan, China, MycoKeys 102, pp. 1-28 : 1

Distoseptispora xinpingensis H.W. Shen & Z.L. Luo sp. nov.

Fig. 8

Etymology.

" xinpingensis " refers to the Xinping Yi and Dai Autonomous County, Yunnan Province, China, where the species was collected.

Description.

Saprobic on submerged decaying wood in a freshwater stream. Anamorph: Colonies on wood effuse, brown to dark brown, solitary or gregarious. Mycelium immersed, composed of septate, hyaline to brown hyphae, smooth-walled. Conidiophores (97-)105-149(-175) × 4-5 µm (x̄ = 127 × 5 µm, n = 40), macronematous, mononematous, solitary or in groups, erect, straight or slightly flexuous, cylindrical, brown, unbranched, slightly paler at the apical cell, slightly enlarged at the base, septate, smooth-walled. Conidiogenous cells (7-)13-23(-25) × 4-5 µm (x̄ = 18 × 4 µm, n = 30), mono- or poly- blastic, terminal, determinate, subcylindrical, pale brown, smooth-walled. Conidia (95-)107-139(-155) × (7-)8-9(-10) µm (x̄ = 123 × 8 µm, n = 40), acrogenous, solitary, obclavate, truncate at base, tapering towards the apex, straight or slightly curved, brown, 8-12-euseptate, smooth, thin-wall, sometimes a second conidium proliferates at the top of the conidia. Teleomorph: Undetermined.

Culture characteristics.

Conidia germinating on PDA within 24 hrs and swollen germ tubes produced from both ends and some septate. Colonies growing on PDA reaching 2-3 cm in two weeks at 26 °C in the dark, with dense, velvety, dark brown mycelium on the surface; in reverse brown to dark brown with entire margin.

Material examined.

China, Yunnan Province, Yuxi City, Xinping Yi and Dai Autonomous County, Yuanjiang River , 23°48′12"N, 101°47′21"E, on submerged decaying branch in a freshwater stream, 22 February 2022, S. Luan & W.P Wang YJ 17-2-2 (HKAS: 125818, holotype), ex-type, KUNCC 22-12667 ; ibid, 23°48′12"N, 101°47′21"E, on submerged decaying branches in a freshwater stream, 22 February 2022, H.W. Shen & Z.Q. Zhang YJ 17-5-2 (HKAS: 125821, paratype), ex-paratype, KUNCC 22-12669 .

Notes.

Phylogenetic analysis showed that the two strains of Distoseptispora xinpingensis (KUNCC 22-12669 and KUNCC 22-12667) clustered together and formed a sister clade to D. lignicola (MFLUCC 18-0198) and D. menghaiensis (HJAUP C2045) with low support (Fig. 1 ). Based on a megablast search of NCBIs GenBank nucleotide database, the best matching result for ITS sequence of KUNCC 22-12667 is Distoseptispora sp. (isolate SICAUCC 22-0049, sequence ID: ON228626; identities: 499/516 (97%), 4 gaps); the best matching result of LSU sequence is D. lignicola (strain MFLUCC 18-0198, sequence ID: MK849797; identities: 1223/1245 (98%), no gap); the best matching result of rpb 2 sequence is D. bambusae (voucher MFLU 17-1653, sequence ID: MT232882; identities: 1047/1047 (100%), no gap); the best matching result of tef 1-α sequence is D. mengsongensis (strain HJAUP C2126, sequence ID: OP961937; identities: 866/916 (95%), no gap). Distoseptispora xinpingensis conforms to the generic concept of Distoseptispora ( Su et al. 2016; Yang et al. 2018, 2021; Luo et al. 2019; Zhang et al. 2022). The morphological comparison between Distoseptispora xinpingensis and the closely related D. lignicola and D. menghaiensis shows that D. xinpingensis has longer conidiophores (105-149 µm vs. 84-124 µm) and conidia (107-139 µm vs. 60-108 µm), and with more conidial septate (8-12 vs. 5-9) than D. lignicola . Distoseptispora xinpingensis can be distinguished from D. menghaiensis by its longer conidiophores (105-149 µm vs. 45.7-82.9 µm) and conidia (107-139 µm vs. 35.7-48.6 µm), as well as conidial septation (8-12-euseptate vs. 4-8-distoseptate) ( Hu et al. 2023). Given the morphological distinctions and evidence from phylogenetic analysis, we introduce Distoseptispora xinpingensis as a new species from the Red River Basin in Yunnan, China.

Figures

Figure 1. Maximum likelihood (ML) tree is based on combined LSU, ITS, tef 1 - α and rpb 2 sequence data. Bootstrap support values with a ML greater than 65 % and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes, shown as " ML / PP ". The tree is rooted to Aquapteridospora fusiformis (MFLUCC 18 - 1606) and A. lignicola (MFLUCC 15 - 0377). New species are indicated in blue and type strains are in bold.

Figure 8. Distoseptispora xinpingensis (HKAS 125818, holotype) a, b colonies on woody substrates c, d conidiophores e, f conidiogenous cells g-k conidia (Arrow in i-k indicate proliferating conidia) l germinating conidium m culture on PDA. Scale bars: 40 μm (c, d); 10 μm (e, f); 30 μm (g-l).